1. Field of the Invention
The present invention relates to a turntable driving device, and more particularly to a turntable driving device for rotating a turntable of a disc player.
2. Description of the Related Art
Usually, a disc player for playing back a disc such as a CD or an MD comprises a turntable on which a disc is to be placed, and a turntable driving device for rotating the turntable. The turntable driving device comprises a motor having a rotation shaft which is to be coupled to the turntable.
In this device, when the motor is driven and the rotation shaft is rotated, the turntable is rotated. At this time, rattling often occurs in the rotation shaft. When the rotation shaft rattles, the turntable is unstably rotated, whereby the playback and record operations on a disc are sometimes adversely affected.
In order to eliminate such rattling of the rotation shaft, techniques have been proposed in JP-2-50865 and JP8-87825.
JP-2-50865 discloses a configuration in which a rotation shaft of a motor is urged in a predetermined direction so as to eliminate rattling of the rotation shaft. In the configuration, there is a possibility that the rotation shaft wobbles in a direction other than the predetermined direction. In a device disclosed in JP-8-87825, a triangular bearing through which a rotation shaft is passed is disposed, and one edge of the bearing is laterally urged by a torsion spring, thereby suppressing rattling of the rotation shaft. Even in a state where the bearing is urged by the torsion spring, however, the bearing can be moved in a direction perpendicular to the urging direction, so that the rotation shaft may wobble.
It is an object of the invention to prevent shaft wobbling from occurring while suppressing rattling of a rotation shaft of a motor.
The turntable driving device according to a first aspect of the invention is a turntable driving device for rotating a turntable of a disc player, and comprises a motor, a bearing, and an urging member. The motor has a rotation shaft which is to be coupled to the turntable. The bearing is placed on a lateral side of the rotation shaft, and has a pair of inclined faces that are opened in a side of the rotation shaft so as to sandwich the rotation shaft, and that are formed to be abuttable against the rotation shaft. The urging member is a member for urging the bearing toward the rotation shaft.
In this device, when the motor is driven and the rotation shaft is rotated, the turntable is rotated. At this time, the bearing receives the urging force of the urging member to laterally press the rotation shaft. Therefore, the rotation shaft is prevented from rattling. The rotation shaft abuts against the pair of inclined faces of the bearing so as to be sandwiched therebetween.
According to this configuration, the rotation shaft is supported at two positions located across the rotation shaft by the pair of inclined faces. Unlike a conventional turntable driving device in which a bearing abuts only at one position against a rotation shaft, therefore, the rotation shaft is not moved with respect to the bearing in a direction different from the urging direction. As a result, wobbling of the rotation shaft can be suppressed.
The turntable driving device according to a second aspect of the invention is configured so that, in the device of the first aspect, the pair of inclined faces are formed into a V-like shape.
In the device, the rotation shaft of the motor is supported by two edges of the V-like portion of the bearing.
According to this configuration, wobbling of the rotation shaft can be suppressed by a simple shape.
The turntable driving device according to a third aspect of the invention is configured so that, in the device of the first or second aspect, when the bearing abuts against the rotation shaft, an intersection of normal lines of the pair of inclined faces coincides with a rotation axis of the rotation shaft.
In the device, when the bearing abuts against the rotation shaft, the intersection of the normal lines of the pair of inclined faces coincides with the rotation axis of the rotation shaft, and hence the rotation shaft is stably rotated.
The turntable driving device according to a fourth aspect of the invention is configured so that, in the device of any one of the first to third aspects, the bearing is formed by a self-lubricating resin.
In the device, since the bearing is formed by a self-lubricating resin, a friction which, when the bearing abuts against the rotation shaft, is produced between the bearing and the rotation shaft is suppressed.
The turntable driving device according to a fifth aspect of the invention is configured so that, in the device of any one of the first to fourth aspects, the self-lubricating resin is a polyacetal resin.
In the device, since a polyacetal resin is used as the self-lubricating resin, the friction between the bearing and the rotation shaft can be reduced.